Carriage for portable nibbler tools



March 9, 1965 1'. B. JOHNSON 3,172,203

CARRIAGE FOR PORTABLE NIBBLER TOOLS I Filed April 5, 1965 E O O 57 1.

INVENTOR.

I 4770?/VE'Y United States Patent O 3,172,203 CARRIAGE FOR PRTABLE NIBBLER TOOLS Thomas B. Johnson, Ambridge, Pa., assignor to H. H. Robertson Company, Pittsburgh, Pa., a corporation of iPennsylvania Filed Apr. 5, 1963, Ser. No. 270,883 2 Claims. (Cl. 30-228) This invention relates to nibbler tools, and more particularly, to an improved carriage for a portable, poweroperated nibbler tool.

Nibbler tools are well known in the metal cutting art, being described in my U.S. Patent 2,750,667. Nibbler tools are utilized for cutting metal sheets by punching (or nibbling) small slugs :of the sheet metal in a continuous line.

Nbbler tools Such nibbler tools generally include a motor housing, a depending jaw having a horizontally disposed anvil, and a vertically reciprocating cutter tool extended from the motor housing forwardly of the jaw. Customarily the anvil will have a female die for receiving the tip of the cutting tool. The jaw is arranged to receive a sheet of metal which is positioned between the anvil and the cutting tool. During reciprocation of the cutting tool, the jaw is advanced into abutment with that edge of the sheet metal which has been exposed by the immediate preceding cut of the cutting tool.

At the present time, nibbler tools are not customarily utilized for making longitudinal cuts in sheet metal licor and roof decking. Instead, such cuts are normally accomplished with flame cutting tools.

One diiiiculty with the nibbler tools has been that there is an appreciable resistance to the lifting of the cutting tool from engagement with the freshly cut metal. The sheet metal tends to rise up with the ascending cutting tool. To offset this difficulty, it has been a practice to provide a stripper element forwardly of the cutting tool and above the anvil. A gap is provided between the stripper element and the anvil. The metal sheet is positioned within the gap. By carefully regulating the gap distance, the sheet metal can be prevented from fluttering up and down as the cutting tool reciprocates. If the gap is excessive, tluttering of the sheet metal will occur unless the sheet metal is quite rigid, in which case the nibbler itself will have a tendency to dance up and down. Sheet metal ilooring and roof deck normally possess some regions of non-uniform thickness caused by deformations of the sheet metal, spot welds and the like. Every deformation `of the sheet metal decking requires special adjustment of the gap distance between the stripper element and the anvil. `Frequently this need for gap distance adjustment yhas not been under-A stood by the nibbler tool operator who accordingly condemns the nibbler tool as ineffective. Where the operator does understand the principles of the nibbler tool, he is constantly adjusting the gap distance.

l The present invention I have provided a spring loaded carriage for such nibbler tools which eliminates the need for stripper elements with their sensitive gap distances. ln addition, nibbler tools equipped with my present carriage will signiiicantly reduce operator fatigue.

The principal object of this invention is to provide a carriage for a nibbler tool.

A further object of this invention is to provide a carriage for a nibbler tool which will enable the tool to be used for making long cuts through sheet metal having non-uniform thickness or deformities.

A further object of this invention is to provide a nibbler ice tool carriage which will reduce the operator fatigue heretofore associated with such tools.

The carriage of this invention in general comprises a rectangular frame having front wheels and rear wheels. The rear wheels are iixed relative to the frame whereas the front wheels are spring loaded and resiliently urged into a position remote from the frame. The frame is` secured to the underside of the motor casing of the nibbler tool with the front Wheels positioned in advance of the motor casing and the rear wheels positioned beneath the motor casing. A11 opening is provided in the frame to receive the jaw, anvil and cutter tool of the nibbler tool. The cutter tool is positioned between the front and rear wheels. The spring loaded front wheels are constantly urged into rolling contact with the upper surface of a metal sheet which is being cut by the nibbler tool. As a result, the undersurface of the metal sheet is con` stantly urged into contact with the upper surface of the anvil, thereby minimizing sheet metal chatter. 'Ihe front and rear wheels cooperatively position the nibbler tool in cutting relation with a metal sheet so that the tool operator need not hold the tool relative to the metal sheet.

The present invention, its objects and advantages, will be more fully described by reference to the accompanying drawings in which:

FIGURE 1 is a side elevation view, partly in cross-1 section, of a metal sheet which is engaged by the present carriage. A nibbler tool, illustrated in phantom outline, is shown secured to the carriage;

FIGURE 2 is a cross-section illustration taken along the line 2 2 -of FIGURE l and showing the frame and the front wheels of the present carriage along with the spring loading mechanism; and

FIGURE 3 is a plan view of the present carriage.

Referring to FIGURE 1, there is illustrated in phantom outline a typical nibbler tool 10 having a motor casing 11 and a handle portion 12. A power cable 13 connects the nibbler tool 10 to a source of electrical power. A jaw portion 14 depends from the motor casing 11 aud terminates in a horizontal anvil portion 15. The anvil portion 15 contains a female die 16.

A reciprocating cutter tool 17 is positioned forwardly on the jaw portion 14 and is adapted for vertical reciprocation into and out of the female die 16. Forwardly of the reciprocating cutter tool 17 is an adjustable stripper element 18. The adjustable stripper element 18 is vertically adjustable relative to the anvil 15 whereby the gap distance between the stripper element 18 and the female die 16 can be adjusted.

As shown in FIGURES l and 2, a pair of contacting metal sheets 19, 20 can be cut by means of the nibbler tool 10 to provide cut edge surfaces 21, 22 which are formed by punched-out slugs of metal which have been nibbled away through the reciprocating action of the cutter tool 17 against the female die 16. It will be observed that the metal sheets 19, 20 abut against the jaw portion 14 between the cutter tool 17 and the female die 16 when the cutter tool 17 is in its elevated position.

According to this invention, the nibbler tool 10 is secured to a carriage which is identified generally by the numeral 30. The carriage 30 includes a frame 31, a pair of front wheels 32 and a pair of rear wheels 33.

As seen in FIGURE 3, the frame may comprise a pair of side angles 34, 35 secured to a rear plate 36 by means of screws 37. The side angles 34, 35 are secured at the front end to a front plate 38 by means of screws 39. The front plate 38 has a central aperture and welded thereabove is a journal 40 having a horizontal bore 41 through the vertical walls thereof.

An aperture 42 is provided in the frame 31 between the side angles 34, 35. A pair of mounting plates 43 may 3 be welded to the side angles I34, 35 to receive screws 44 (FIGURE 1) 4which secure the carriage 30 to the underside of the nibbler tool motor casing 11. The jaw portion 14, the anvil 15 and thercc'iprocating' cutter tool 17 are received in the aperture Y Y Welded to the underside of the rear plate 36 is a journaled lug 45 which receives a shaft 46.- A pair of wheels or rollers 33 is secured to the outboard ends of the shaft 46. Ideally the rear Wheels 33 comprise a standard ball bearing element having an inner race 48 and an outer race 49. The inner race 4S is secured to the shaft 46 whereas the outer race 49 serves as the rim portion of the wheels 33.

A vertical shaft 50 lits into the journal 49 and is secured at its bottom portion to a journaled lug 51. A horizontal shaft 52 is secured within the journaled lug 51 to receive at its outboard ends a pair of front wheels or rollers 32. Ideally the front wheels 32 likewise comprise conventional ball bearing elements having an inner race 54 and an outer race 55. The inner race 54 is secured to the shaft 52 whereas the outer race 55 serves as the perimeter or" the wheels 32 in engagement with the sheet metal 19, 20 which is being cut.

A long slot 56 is provided entirely through the vertical shaft 50. A pintle 57 extends through the horizontal bore 41 and through the long slot 56 to secure the vertical shaft 50 within the bore of the journal 40. A cotter pin 58 prevents withdrawal of the pintle 57. The pintle '7 and slot 56 serve as a stop means for limiting the movement of the vertical shaft 5t).

The vertical shaft 50 is vertically moveable from one extreme position as shown in FIGURE 2 where the pintle 57 is in abutment with the upper end of the slot 56 to the other extreme position where the pintle 57 would be in Contact with the bottom end of the slot 576.

A compressed coil spring 59 abuts the frame 31 at its upper end and abuts the journaled lug 51 at its lower end thereby constantly resiliently urging the journaled lug 51 to a position remote from the frame 31, i.e., a position as shown in FIGURE 2 Where the pintle 57 is in engagement with the upper end of the slot 56.

A spring compression of about 125 pounds is desirable -in the spring59 for vcutting metal sheets up to about 3/15 inch thickness.

Operalz'on Referring once vmore to FIGURE 1, the front wheels 32 and the -rear wheels 33 are constantly in peripheral conthe .bottom metal sheet 20. As .the reciprocating cutter tool `17 is drawn vertically upwardly away from the female die 16, the compressive ,force of the spring 59 urges the metal sheets 19, 20 against the female die 16 thereby allowing the reciprocating cutter tool 17 to separate away from the metalsheets 19, .20.

In the event spot welds, discontinuities or deformities should appear in the metal sheets 19, 20 the front wheels 32 will rise .over such non-uniformities yet maintain the undersurface of the metal sheet 26 in continuing abutment with the female die 16. Hence there is no need whatsoever for the adjustable stripper element 18 in the nibbler tool which is equipped with the present carriage.

Moreover with the Vpresent carriage, there is no need for the nibbler tool `operator to` hold the nibbler tool 10 in his hands ata spaced distance above the metal sheets 19, 20 which are being cut. Instead, the nibbler tool 10 rests upon the carriage 30 inthe desired spaced relation above the metal sheets. All that is required for the operator is to provide a forward impetus for the carriage mounted tool in the direction of the desired cut.

Nibbler` toois with the present carriage structure can be used for cutting mild steel in thicknesses up to about 3/16- inch. One-quarter inch plates also have beencut with the carriageV mounted nibbler tool.

If the coil spring .S9 is too strong, the nibbler tool will be difficult to `push along the line of cutting. Where l the spring is not strong enough, the cutting tool will not be readily extracted from the sheet metal and a resulting flutter of the sheet metal or dancing of the nibbler machine will be manifested without any useful cutting action.

Comparative results `A nibbler tool equipped with the present carriage was utilized in the cutting of sheet metal cellular ooring. The nibbler tool accomplished the desired cutting in about onefth of the time required for accomplishing the same cut with tiame cutting apparatus.

The nibbler-tool carriage of this invention is especially useful in effecting lengthwise cuts in sheet metal decking and flooring. A typical sheet metal oor decking is illustrated in FIGURE 2 wherein the upper corrugated sheet 6i) is joined Ywith the lower Acorrugated sheet 61 along a common web portion 19, 20. The generally vertical side surfaces 62 of the upper sheet 60 `define a channel in which the carriage 30 is operable. The rollers S3 are relatively confined between the generally vertical sides 62 and thereby serve as a means for conveniently aligning the resulting cut along the center of the common web portion 19, 20.

I claim:

1. A carriage for use in combination with a portable power-operated nibbler tool, which nibbler tool comprises:

a motor housing;

a jaw depending therefrom;

a horizontally disposed anvil supported by said jaw;

a vertically reciprocating cutter tool extended from said motor housing forwardly of said jaw;

said Yanvil having a female die for receiving the tip of said cutting tool;

said jaw being adapted to receive a sheet of metal positioned between 4the said anvil and the said cutting tool;

the said carriage comprising:

a frame secured to the underside of said motor housing and extending forwardly beyond the front of said motor housing;

xed roller means extended beneath said frame and secured to the rear of said frame lbeneath the said motor housing;

vertically moveable roller means extended beneath said frame and slideably secured to the front of said frame forwardly of said motor housing and forwardly of said jaw, the said movable roller means being adapted for vertical movement relative to the said frame;

stop means limiting the range of movement of said movable roller means relative to said frame; and

a central opening in the said frame for receiving the said jaw and cutting tool.

2. A carriage for use in combination with a portable power-operated nibbler tool, which nibbler tool comprises:

a motor housing;

a jaw dependingtherefrom;

a horizontally ydisposed anvil supported by said jaw;

a vertically reciprocating cutter tool extended from said motor housing forwardly of said jaw;

said anvil having a female die for receiving the tip of said cutting tool;

said jaw being adapted to receive a sheet of metal positioned between the said anvil and the said cutting tool;

the said carriage comprising:

a frame secured to the underside ofsaid motor housing and extending forwardly beyond the front of said motor housing;

xed roller rmeans extended beneath said frame and secured to the rear of said frame beneath the said motor housing;

vertically movable roller means extended beneath said frame and slideably secured to the front of said frame forwardly of the said motor housing and forwardly of the said jaw, the said moveable roller means being adapted for vertical movement relative to the said frame;

stop means limiting the range of movement of said moveable roller means relative to the said frame;

a central opening in the said frame for receiving the said jaw and cutting tool; and

resilient means interposed between the said frame and the said moveable roller means for constantly urg- 10 ing the said roller means downwardly away from the said frame.

References Cited in the file of this patent UNITED STATES PATENTS 722,475 Wright Mar. 10, 1903 2,750,667 Johnson `lune 19, 1956 3,097,430 Lewinski et al July 16, 1963 

1. A CARRIAGE FOR USE IN COMBINATION WITH A PORTABLE POWER-OPERATED NIBBLER TOOL, WHICH NIBBLER TOOL COMPRISES: A MOTOR HOUSING; A JAW DEPENDING THEREFROM; A HORIZONTALLY DISPOSED ANVIL SUPPORTED BY SAID JAW; A VERTICALLY RECIPROCATING CUTTER TOOL EXTENDED FROM SAID MOTOR HOUSING FORWARDLY OF SAID JAW; SAID ANVIL HAVING A FEMALE DIE FOR RECEIVING THE TIP OF SAID CUTTING TOOL; SAID JAW BEING ADAPTED TO RECEIVE A SHEET OF METAL POSITIONED BETWEEN THE SAID ANVIL AND THE SAID CUTTING TOOL; THE SAID CARRAIGE COMPRISING: A FRAME SECURED TO THE UNDERSIDE OF SAID MOTOR HOUSING AND EXTENDING FORWARDLY BEYOND THE FRONT OF SAID MOTOR HOUSING; 